US6297901B1 - Optical attenuating isolator - Google Patents

Optical attenuating isolator Download PDF

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Publication number
US6297901B1
US6297901B1 US09/482,532 US48253200A US6297901B1 US 6297901 B1 US6297901 B1 US 6297901B1 US 48253200 A US48253200 A US 48253200A US 6297901 B1 US6297901 B1 US 6297901B1
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United States
Prior art keywords
light
optical
collimator
attenuating
isolator
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US09/482,532
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English (en)
Inventor
Jeong-mee Kim
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Assigned to SAMSUNG ELECTRONICS CO., LTD. reassignment SAMSUNG ELECTRONICS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KIM, JEONG-MEE
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/09—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on magneto-optical elements, e.g. exhibiting Faraday effect
    • G02F1/093—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on magneto-optical elements, e.g. exhibiting Faraday effect used as non-reciprocal devices, e.g. optical isolators, circulators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/27—Optical coupling means with polarisation selective and adjusting means
    • G02B6/2746—Optical coupling means with polarisation selective and adjusting means comprising non-reciprocal devices, e.g. isolators, FRM, circulators, quasi-isolators
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/264—Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting
    • G02B6/266—Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting the optical element being an attenuator
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2203/00—Function characteristic
    • G02F2203/48—Variable attenuator

Definitions

  • the present invention relates to an optical component which is used for optical transmission, and more particularly, to an optical component formed by combining an optical attenuator and an isolator, the optical component used as a module.
  • WDM wavelength division multiplexing
  • an optical add drop multiplexer requires as many optical attenuators and isolators as the number of channels, thus increasing the total size of the apparatus.
  • a further object of the invention is to provide an optical attenuating isolator which does not suffer from back-reflection problems of the attenuator.
  • a yet further object is to provide an optical attenuating isolator with low insertion loss.
  • a still further object is to provide an optical attenuating isolator of reduced size.
  • Another object is to provide an optical attenuating isolator of reduced cost.
  • an optical attenuating isolator including: a first collimator connected to a first optical transmission medium, the first collimator for collimating light received via the first optical transmission medium; an optical attenuating filter for attenuating the output light of the first collimator; an isolation unit for receiving light attenuated by the optical attenuating filter and passing only polarized light which is polarized in a predetermined specific polarization direction; and a second collimator connected to a second optical transmission medium, the second collimator for collimating polarized light which has passed through the isolation unit, and transmitting the resultant light to the second optical transmission medium.
  • an optical attenuating isolator including: a first collimator connected to a first optical transmission medium, the first collimator for collimating light received via the first optical transmission medium; an isolation unit for receiving the output light of the first collimator and passing only polarized light which is polarized in a predetermined specific polarization direction; an optical attenuating filter for attenuating polarized light which has passed through the isolation unit; and a second collimator connected to a second optical transmission medium, the second collimator for collimating polarized light which has passed through the optical attenuating filter, and transmitting the resultant light to the second optical transmission medium.
  • an optical attenuating isolator including: a polarizer for passing only light which is polarized in a direction that is the same as the direction of polarization of the polarizer, among the received light; an optical attenuating filter for attenuating polarized light which has passed through the polarizer; a Faraday rotator for rotating attenuated light which has passed through the optical attenuating filter by a predetermined number of degrees; and an analyzer for passing only light which is polarized in a direction that is the same as the direction of the analyzer, from among the rotated light.
  • an optical attenuating isolator including: a polarizer for passing only light which is polarized in a direction that is the same as the direction of polarization of the polarizer, among the received light; a Faraday rotator for rotating polarized light which has passed through the polarizer by a predetermined number of degrees; an optical attenuating filter for attenuating light which has passed through the Faraday rotator; and an analyzer for passing only light which is polarized in a direction that is the same as the direction of the analyzer, among the light received from the optical attenuating filter.
  • FIG. 1 is a block diagram illustrating the configuration of an isolator
  • FIG. 2 is a block diagram illustrating the configuration of a variable optical attenuator
  • FIG. 3 is a block diagram illustrating the configuration of an optical attenuating isolator which performs both optical attenuation and isolation, according to an embodiment of the present invention
  • FIG. 4 is a block diagram illustrating the configuration of an optical attenuating isolator which performs both optical attenuation and isolation, according to another embodiment of the present invention
  • FIG. 5 is a block diagram illustrating the configuration of an optical attenuating isolator which performs both optical attenuation and isolation, according to still another embodiment of the present invention
  • FIG. 6 is a block diagram illustrating the configuration of an optical attenuating isolator which performs both optical attenuation and isolation, according to yet another embodiment of the present invention.
  • Isolators cause low loss with respect to light transmitted in a normal direction from an input projection terminal to an output terminal, and high loss with respect to light transmitted in the reverse direction to the normal direction, in order to prevent light from flowing backward and from recombining. Therefore, isolators are optical components for stabilizing the operation of a system.
  • An isolator shown in FIG. 1 includes a first collimator 100 , a polarizer 110 , a Faraday rotator 120 , an analyzer 130 , and a second collimator 140 .
  • the polarizer 110 and the analyzer 130 are rotated 45° with respect to each other, and keep this relative position.
  • isolators transmit only specific polarized light in one direction, and prevent the passage of polarized light in a direction that is perpendicular to the direction of the polarized light.
  • the Faraday rotator 120 rotates incident polarized light by 45°. Light reflected by the output terminal of the isolator enters the rear side of the Faraday rotator 120 , and is again rotated 45°. Consequently, the reflected light is rotated 90° with respect to the incident light. Hence, the 90°-rotated reflected wave is blocked by the polarizer 110 .
  • the Faraday rotator 120 uses a Faraday effect in which the polarized surface of light is rotated while the light passes through a magneto-optic material.
  • FIG. 2 shows a variable optical attenuator.
  • the variable optical attenuator includes a first collimator 200 , a linear variable neutral density filter 210 , and a second collimator 220 .
  • the first collimator 200 receives light from an optical fiber, collimates the received light, and transmits the collimated light to the linear variable neutral density filter 210 .
  • the linear variable neutral density filter 210 variably attenuates the collimated light and transmits the resultant light to the second collimator 220 .
  • the second collimator 220 collimates the attenuated light to an optical fiber.
  • the variable optical attenuator can constantly attenuate optical signals through the above-described operation.
  • the intensity of this attenuation is variable.
  • the variable optical attenuator is used for measurement of the characteristics of an optical communications system.
  • FIG. 3 shows an optical attenuating isolator according to an embodiment of the present invention, which includes a first optical transmission medium 300 , a first collimator 310 , an optical attenuating filter 320 , an isolation unit 330 , a second collimator 340 , and a second optical transmission medium 350 .
  • Light is applied to the first collimator 310 via the first optical transmission medium 300 which is an optical fiber or a waveguide.
  • the first collimator 310 collimates received light, and transmits the collimated light to the optical attenuating filter 320 .
  • the optical attenuating filter 320 can variably attenuate the collimated light. The degree of this attenuation can be controlled by turning a screw which is installed on the exterior of the optical attenuating isolator module according to the present invention.
  • the attenuated light is transmitted to the isolation unit 330 .
  • the isolation unit 330 includes a polarizer, a Faraday rotator, and an analyzer. Thus, the isolation unit 330 passes only specific polarized light in a direction which is the same as the predetermined direction of polarization to be performed by the polarizer, and prevents the passage of polarized light which is polarized perpendicular to the polarization direction of the polarizer. Light which has passed through the isolation unit 330 is collimated by the second collimator 340 , and the resultant light is transmitted to the second optical transmission medium 350 .
  • FIG. 4 shows an optical attenuating isolator according to another embodiment of the present invention, which includes a first optical transmission medium 400 , a first collimator 410 , an isolation unit 420 , an optical attenuating filter 430 , a second collimator 440 , and a second optical transmission medium 450 .
  • the embodiment shown in FIG. 4 is the same as that shown in FIG. 3 except that the positions of the optical attenuating filters 320 and 430 are different. That is, in the embodiment shown in FIG. 4, the optical attenuating filter 430 is positioned to the rear of the isolation unit 420 . On the other hand, in the embodiment shown in FIG. 3, the optical attenuating filter 320 is positioned in front of the isolation unit 330 . Hence, attenuation before isolation, as shown in FIG. 3, is compared with attenuation after isolation, as shown in FIG. 4 .
  • the optical attenuating isolator of FIG. 3 or 4 can be manufactured according to the convenience of a process for manufacturing the optical attenuating isolator.
  • FIG. 5 shows an optical attenuating isolator according to still another embodiment of the present invention, which includes a first optical transmission medium 500 , a first collimator 510 , a polarizer 520 , an optical attenuating filter 530 , a Faraday rotator 540 , an analyzer 550 , a second collimator 560 , and a second optical transmission medium 570 .
  • the embodiment shown in FIG. 5 is obtained by further installing an optical attenuating filter between the components constituting the isolation unit 330 or 420 shown in FIG. 3 or 4 .
  • the isolation unit 330 or 420 performs independent isolation.
  • a filter is installed between the components of the isolation unit, and performs attenuation before or after the operation of each isolator component.
  • light is applied to the first collimator 510 via the first optical transmission medium 500 which is an optical fiber or a waveguide.
  • the first collimator 510 collimates received light and transmits the collimated light to the polarizer 520 .
  • the polarizer 520 selectively passes only light beams whose polarized direction is the same as the polarization direction of the polarizer, of the received light beams.
  • the optical attenuating filter 530 can variably attenuate the polarized light.
  • the degree of this attenuation can be controlled by turning a screw which is installed on the exterior of the optical attenuating isolator module according to the present invention.
  • the attenuated light is applied to the Faraday rotator 540 .
  • the Faraday rotator 540 rotates received light by 45° from the polarization direction of the light entering the Faraday rotator.
  • the 45°-rotated light is applied to the analyzer 550 . Only polarized light whose polarized direction that is the same as the polarization direction of the analyzer 550 , passes through the analyzer 550 .
  • the second collimator 560 collimates the polarized light which has passed through the analyzer 550 , and transmits the resultant light to the second optical transmission medium 570 .
  • FIG. 6 shows an optical attenuating isolator according to yet another embodiment of the present invention, which includes a first optical transmission medium 600 , a first collimator 610 , a polarizer 620 , a Faraday rotator 630 , an optical attenuating filter 640 , an analyzer 650 , a second collimator 660 , and a second optical transmission medium 670 .
  • FIG. 6 The embodiment shown in FIG. 6 is the same as that shown in FIG. 5 except that the optical attenuating filter 640 is installed behind the Faraday rotator 630 . Likewise, the optical attenuating isolator of FIG. 5 or 6 will be able to be selectively manufactured according to the convenience of a manufacturing process.
  • variable optical attenuation can be performed by controlling a linear variable neutral density filter, and simultaneously, the function of isolation can be performed using first and second collimators, a polarizer, a Faraday rotator, and an analyzer. Consequently, optical attenuating isolators according to the present invention are capable of variably determining the degree of optical attenuation.
  • an optical attenuator and an isolator are configured into a module, such that insertion loss can be reduced, and that the number of optical transmission media used is reduced, thus preventing generation of loss caused by the optical transmission media.
  • an optical attenuating isolator according to the present invention is used as an optical attenuator for an optical communications system having directivity, such that a deterioration of light of the optical communications system due to back reflection can be prevented, and that the degree of attenuation can be controlled.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
US09/482,532 1999-01-14 2000-01-14 Optical attenuating isolator Expired - Fee Related US6297901B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1019990000846A KR20000050764A (ko) 1999-01-14 1999-01-14 광감쇠 아이솔레이터
KR99-846 1999-01-14

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US6297901B1 true US6297901B1 (en) 2001-10-02

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Country Status (6)

Country Link
US (1) US6297901B1 (de)
KR (1) KR20000050764A (de)
CN (1) CN1131446C (de)
DE (1) DE10001389B4 (de)
FR (1) FR2788606A1 (de)
GB (1) GB2345761B (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040051932A1 (en) * 2002-09-03 2004-03-18 Andrew Harker Integrated variable optical attenuator and isolator, components therefor and method of assembly
US20040086256A1 (en) * 2002-10-30 2004-05-06 Gustavson Todd L. Continuously variable attenuation of an optical signal using an optical isolator
US20050111073A1 (en) * 2003-11-20 2005-05-26 Lightwaves 2020, Inc., Corporation Of California Integrated variable optical attenuator and related components
US7099539B1 (en) 2003-07-07 2006-08-29 Super Talent Electronics, Inc. Optical isolator, attenuator and polarizer system and method for integrated optics
US20130170785A1 (en) * 2010-01-28 2013-07-04 Peiliang GAO Multifunctional integrated optical device
CN105938973A (zh) * 2016-06-21 2016-09-14 沈阳理工大学 一种新型高精度激光能量/功率衰减器

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4683421A (en) * 1985-03-29 1987-07-28 Westinghouse Electric Corp. Drift compensation technique for a magneto-optic current sensor
JPH04246615A (ja) 1991-01-31 1992-09-02 Fuji Elelctrochem Co Ltd 光アイソレータ
JPH08128806A (ja) 1994-10-31 1996-05-21 Ricoh Co Ltd 光学式変位センサ
JPH09210857A (ja) 1996-02-06 1997-08-15 Nippon Telegr & Teleph Corp <Ntt> 多モード光ファイバの接続トレランス測定装置及び測定方法
US5812304A (en) * 1995-08-29 1998-09-22 Fujitsu Limited Faraday rotator which generates a uniform magnetic field in a magnetic optical element
US5889609A (en) * 1992-07-31 1999-03-30 Fujitsu Limited Optical attenuator
JPH11236784A (ja) 1998-02-20 1999-08-31 Asmo Co Ltd 挟み込み検出装置
US5973821A (en) * 1996-03-01 1999-10-26 Fujitsu Limited Variable optical attenuator which applies a magnetic field to a faraday element to rotate the polarization of light signal
US6018411A (en) * 1996-11-29 2000-01-25 Fujitsu Limited Optical device utilizing magneto-optical effect
US6195479B1 (en) * 1999-06-28 2001-02-27 E-Tek Dynamics, Inc. Fiberoptic reflective variable attenuator and on-off switch

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JPS62278528A (ja) * 1986-05-27 1987-12-03 Copal Electron Co Ltd レ−ザビ−ム強度分布変換方法
US4981335A (en) * 1989-10-17 1991-01-01 At&T Bell Laboratories Optical package arrangement with reduced reflections
JPH03273208A (ja) * 1990-03-23 1991-12-04 Nec Corp 半導体レーザモジュール
JPH04369615A (ja) * 1991-06-19 1992-12-22 Matsushita Electric Ind Co Ltd 光アイソレータ
JPH04371911A (ja) * 1991-06-21 1992-12-24 Hitachi Ltd 光アイソレータおよび希土類添加ファイバ光増幅装置
JPH08172233A (ja) * 1994-12-15 1996-07-02 Anritsu Corp 可変波長光源装置
JP2850891B2 (ja) * 1996-12-10 1999-01-27 日本電気株式会社 光フィルタモジュールとこれを用いた光増幅装置
KR100274810B1 (ko) * 1997-12-09 2000-12-15 윤종용 아이솔레이터를이용한광감쇠기및이를구비한광통신시스템

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4683421A (en) * 1985-03-29 1987-07-28 Westinghouse Electric Corp. Drift compensation technique for a magneto-optic current sensor
JPH04246615A (ja) 1991-01-31 1992-09-02 Fuji Elelctrochem Co Ltd 光アイソレータ
US5889609A (en) * 1992-07-31 1999-03-30 Fujitsu Limited Optical attenuator
US6018412A (en) * 1992-07-31 2000-01-25 Fujitsu Limited Optical attenuator
JPH08128806A (ja) 1994-10-31 1996-05-21 Ricoh Co Ltd 光学式変位センサ
US5812304A (en) * 1995-08-29 1998-09-22 Fujitsu Limited Faraday rotator which generates a uniform magnetic field in a magnetic optical element
JPH09210857A (ja) 1996-02-06 1997-08-15 Nippon Telegr & Teleph Corp <Ntt> 多モード光ファイバの接続トレランス測定装置及び測定方法
US5973821A (en) * 1996-03-01 1999-10-26 Fujitsu Limited Variable optical attenuator which applies a magnetic field to a faraday element to rotate the polarization of light signal
US6018411A (en) * 1996-11-29 2000-01-25 Fujitsu Limited Optical device utilizing magneto-optical effect
JPH11236784A (ja) 1998-02-20 1999-08-31 Asmo Co Ltd 挟み込み検出装置
US6195479B1 (en) * 1999-06-28 2001-02-27 E-Tek Dynamics, Inc. Fiberoptic reflective variable attenuator and on-off switch

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040051932A1 (en) * 2002-09-03 2004-03-18 Andrew Harker Integrated variable optical attenuator and isolator, components therefor and method of assembly
US20040086256A1 (en) * 2002-10-30 2004-05-06 Gustavson Todd L. Continuously variable attenuation of an optical signal using an optical isolator
US7050694B2 (en) 2002-10-30 2006-05-23 Finisar Corporation Continuously variable attenuation of an optical signal using an optical isolator
US7099539B1 (en) 2003-07-07 2006-08-29 Super Talent Electronics, Inc. Optical isolator, attenuator and polarizer system and method for integrated optics
US20050111073A1 (en) * 2003-11-20 2005-05-26 Lightwaves 2020, Inc., Corporation Of California Integrated variable optical attenuator and related components
US20130170785A1 (en) * 2010-01-28 2013-07-04 Peiliang GAO Multifunctional integrated optical device
CN105938973A (zh) * 2016-06-21 2016-09-14 沈阳理工大学 一种新型高精度激光能量/功率衰减器

Also Published As

Publication number Publication date
FR2788606A1 (fr) 2000-07-21
GB0000616D0 (en) 2000-03-01
DE10001389B4 (de) 2004-12-30
GB2345761A (en) 2000-07-19
CN1131446C (zh) 2003-12-17
KR20000050764A (ko) 2000-08-05
CN1260499A (zh) 2000-07-19
DE10001389A1 (de) 2000-07-27
GB2345761B (en) 2001-04-25

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